flashing taskbar

Today when I went onto my computer, and was using AIM when i received new im's it no longer flashed orange at the bottom to tell me... i tested it in all of the programs i know use this to warn me of things and none of them flash anymore. What could casue this... i didn't install anything.

Many programs will cause this when they are displayed in FULL SCREEN mode,
and a dialog box needs to be displayed. The dialog box is under neath the full screen and the flashing is to alert you to use the smaller display so you may see the dialog.

For reasons like this, I seldom use FS to allow access to other icons and directories